Warn that a failed NaN test may not be an error

Sprintf returns "-nan" rather than "nan" on some platforms, which causes
the test script to incorrectly flag a failure.

Also allow test functions without "==> Config" output.

2 files changed, 9 insertions, 3 deletions

diff --git a/tests/common.lua b/tests/common.lua
index 156f882..47e3f56 100644
--- a/tests/common.lua
+++ b/tests/common.lua
@@ -231,7 +231,9 @@ end
 function run_test_group(testgroup, tests)
     local function run_config(configname, func)
         local success, msg = pcall(func)
-        print(string.format("==> Config %s: %s", configname, msg))
+        if msg then
+            print(string.format("==> Config %s: %s", configname, msg))
+        end
         print()
     end
 
diff --git a/tests/test.lua b/tests/test.lua
index bfa4f66..19f5eca 100755
--- a/tests/test.lua
+++ b/tests/test.lua
@@ -147,9 +147,13 @@ local encode_error_tests = {
       false, { "Cannot serialise number: must not be NaN or Inf" } },
     function ()
         json.refuse_invalid_numbers(false)
-        return 'Setting refuse_invalid_numbers(false)'
+        return 'Setting refuse_invalid_numbers(false).'
     end,
-    { json.encode, { NaN }, true, { "-nan" } },
+    function ()
+        print('NOTE: receiving "-nan" is ok..')
+        return
+    end,
+    { json.encode, { NaN }, true, { "nan" } },
     { json.encode, { Inf }, true, { "inf" } },
     function ()
         json.refuse_invalid_numbers("encode")